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parport: ieee1284: use del_timer_sync() in parport_wait_event()

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Use del_timer_sync() instead of del_timer() to make sure the timer won't
be running when we return from parport_wait_event(), because this would
crash due to destruction of timer_list.

This is untested and just based on a code review.  Just think about the
following sequence of events:

- add_timer()

- down_interruptible() is interrupted by a signal.

- we enter the timer callback handler on another CPU.

- del_timer(), but the timer callback is still running.

- eturn from parport_wait_even, which destroys the automatic variable
  "timer" while the callback is running on another CPU.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michael Buesch 2009-01-06 14:43:14 -08:00 committed by Linus Torvalds
parent 50682bb4de
commit f59abb161c
1 changed files with 1 additions and 1 deletions
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2
drivers/parport/ieee1284.c
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@ -84,7 +84,7 @@ int parport_wait_event (struct parport *port, signed long timeout)
add_timer (&timer);
ret = down_interruptible (&port->physport->ieee1284.irq);
if (!del_timer (&timer) && !ret)
if (!del_timer_sync(&timer) && !ret)
/* Timed out. */
ret = 1;